Our new Audio Answers is up on our website and we hope you find it useful. we will feature a new topic each week, below is our first article.
Hey all,
With this being my first article for this website, I have decided to touch base on a simple topic that a lot of enthusiasts don't completely understand..the ported vs. sealed misconception. Lots of enthusiasts argue the benefits of each every day, but they do so with uneducated facts. Here I won't give the advantages and disadvantages of each, rather just give facts as to what each does. This way one can draw their own conclusions as to which they would rather use.
For those who don't know what these are, here is a little refresher. The two most common enclosure types that are used in audio systems are ported (or vented) and sealed (or air-suspension or acoustic-suspension). A sealed enclosure is simply that where the entire enclosure is airtight, with no vents or holes of any kind. This is what you will commonly see people using, as they have not built their own and are using a pre-fabricated box. Sealed enclosures tightly regulate the suspension of the woofer, as the air inside the box is always trying to equal its pressure to that of the atmosphere.
Typically, the bigger the enclosure is, more low-end output is produced at the expense of the amount of power that can be allocated to the woofer. The larger box limits throw less, and excursion is increased. This results in an overall lower box Qtc (Q quotient), which is a more advanced topic I will discuss later.
The smaller a sealed enclosure is, the more controlled the woofer's stroke is. Driver excursion is limited, and response is generally more punchy. Because of this limit in excursion, more power can safely be allocated to the woofer through means of an amplifier.
A ported enclosure is that which is "tuned" to a specific frequency within the frequency range. This tune usually ranges anywhere from 25 Hz all the way up to 50 Hz, which is the optimal range for producing bass. This tuning is accomplished by means of a port, which acts as a bass reflex to amplify the sound produced. This port utilizes the rear sound waves that come out of the back of the subwoofer, thus effectively increasing output, among other things.
This kind of enclosure is tuned by adjusting the dimensions of the port in relation to the internal net volume of air inside the box. This change is affecting the way the port resists motion, thus tuning the box. Tuning a box in this way however, does limit the frequency range where the most output can be achieved. When the factors are put together, the rear waves from the subwoofer are delayed so that the front waves and the port waves are constructive and compliment each other.
Designing a useful ported enclosure is much more complicated than a sealed, so making one is usually only for experienced enthusiasts who have calculated the factors correctly. However, doing so can cause a large increase in output over the main frequency range of bass, usually 3-6 decibels.
Some people like to claim that one enclosure type is better than the other, but this is just not true. Both have their ups and downs and in-betweens.
For questions for Audio Answers email audioanswers@mycarjams.com
www.mycarjams.com
Replies (8)
mycarjams.com on 07/23/2004 01:00:33
uochronos on 07/23/2004 01:12:45
i'm confused about this post? is this some sort of advertisement for your site? if you well look we have several similar articles in are DIY section.
we always like new views and input. and we enjoy seeing other opinions and new ideas. i just would hate to see this turn into some type of spaming. assuming it wont then i perosnaly welcome your input and views.
mycarjams.com on 07/23/2004 01:18:20
I tried posting this DIY, did not think that it went through, I do have a site but am also an Car Audio enthusiast and like to share my knowledge, sorry if I broke any rules.
uochronos on 07/23/2004 01:29:23
nope no rules broken. just had a few people in recent months post spam... sharing of knowledge is what we are all about feel free to share anytime we love new points of view... i just like to make sure no spaming happens.
nice to have you hear though since its pretty obvious now that spamming is not what you are about. welcome to are group. if you havent been here before i'm sure you well be pretty impressed with the pool of minds we have here.
we are all about helping the people new to this and learning new stuff ourselves as we go. and its always nice to haev someone new around.
mycarjams.com on 07/23/2004 01:35:15
Thanks for the welcome, I am putting together an information area on my site and am going to post a new subject every week, I have been a visitor here a few times and figured that they would benefit the members you have. Would it be better if I put these in the article section? I treid that and I did not see it post, do these need approved before they are posted?
uochronos on 07/23/2004 01:47:54
i have never posted one but i believe admin has to actualy input it after its submited and he has alot one his plate right now so sometimes it takes awhile to get posted.... that would problay be the best place for stuff like this since it would give more people an oportunity to read it.
i just checked out www.mycarjams.com very interesting site and good prices.
mycarjams.com on 07/23/2004 01:50:54
Thanks, site is only 45 days old, I have a wholesaler close to me that is giving me great prices, only problem is they do not carry all the high end lines, as time goes on I would like to get more quality items up.
swez on 07/23/2004 20:06:49
I see you carry Kole Audio, Power Acoustik and SPL. How do these products compare to brands like Infinty, Alpine, JBL and other well known brands.
See a lot of Pyle, Legacy, Pioneer,Sony and a spate of other low cost amps. Any chance you'll be adding some of the top drawer brands and gear later?
See that the store offers Stiffening Caps. In your opinion, how effective are they and when is is appropriate to use a Power Cap?
Nice site you have started there MCJ. Welcome to CK and like to hear more from you as time permits.
Swez
Hey all,
With this being my first article for this website, I have decided to touch base on a simple topic that a lot of enthusiasts don't completely understand..the ported vs. sealed misconception. Lots of enthusiasts argue the benefits of each every day, but they do so with uneducated facts. Here I won't give the advantages and disadvantages of each, rather just give facts as to what each does. This way one can draw their own conclusions as to which they would rather use.
For those who don't know what these are, here is a little refresher. The two most common enclosure types that are used in audio systems are ported (or vented) and sealed (or air-suspension or acoustic-suspension). A sealed enclosure is simply that where the entire enclosure is airtight, with no vents or holes of any kind. This is what you will commonly see people using, as they have not built their own and are using a pre-fabricated box. Sealed enclosures tightly regulate the suspension of the woofer, as the air inside the box is always trying to equal its pressure to that of the atmosphere.
Typically, the bigger the enclosure is, more low-end output is produced at the expense of the amount of power that can be allocated to the woofer. The larger box limits throw less, and excursion is increased. This results in an overall lower box Qtc (Q quotient), which is a more advanced topic I will discuss later.
The smaller a sealed enclosure is, the more controlled the woofer's stroke is. Driver excursion is limited, and response is generally more punchy. Because of this limit in excursion, more power can safely be allocated to the woofer through means of an amplifier.
A ported enclosure is that which is "tuned" to a specific frequency within the frequency range. This tune usually ranges anywhere from 25 Hz all the way up to 50 Hz, which is the optimal range for producing bass. This tuning is accomplished by means of a port, which acts as a bass reflex to amplify the sound produced. This port utilizes the rear sound waves that come out of the back of the subwoofer, thus effectively increasing output, among other things.
This kind of enclosure is tuned by adjusting the dimensions of the port in relation to the internal net volume of air inside the box. This change is affecting the way the port resists motion, thus tuning the box. Tuning a box in this way however, does limit the frequency range where the most output can be achieved. When the factors are put together, the rear waves from the subwoofer are delayed so that the front waves and the port waves are constructive and compliment each other.
Designing a useful ported enclosure is much more complicated than a sealed, so making one is usually only for experienced enthusiasts who have calculated the factors correctly. However, doing so can cause a large increase in output over the main frequency range of bass, usually 3-6 decibels.
Some people like to claim that one enclosure type is better than the other, but this is just not true. Both have their ups and downs and in-betweens.
For questions for Audio Answers email audioanswers@mycarjams.com
www.mycarjams.com
Replies (8)
mycarjams.com on 07/23/2004 01:00:33
uochronos on 07/23/2004 01:12:45
i'm confused about this post? is this some sort of advertisement for your site? if you well look we have several similar articles in are DIY section.
we always like new views and input. and we enjoy seeing other opinions and new ideas. i just would hate to see this turn into some type of spaming. assuming it wont then i perosnaly welcome your input and views.
mycarjams.com on 07/23/2004 01:18:20
I tried posting this DIY, did not think that it went through, I do have a site but am also an Car Audio enthusiast and like to share my knowledge, sorry if I broke any rules.
uochronos on 07/23/2004 01:29:23
nope no rules broken. just had a few people in recent months post spam... sharing of knowledge is what we are all about feel free to share anytime we love new points of view... i just like to make sure no spaming happens.
nice to have you hear though since its pretty obvious now that spamming is not what you are about. welcome to are group. if you havent been here before i'm sure you well be pretty impressed with the pool of minds we have here.
we are all about helping the people new to this and learning new stuff ourselves as we go. and its always nice to haev someone new around.
mycarjams.com on 07/23/2004 01:35:15
Thanks for the welcome, I am putting together an information area on my site and am going to post a new subject every week, I have been a visitor here a few times and figured that they would benefit the members you have. Would it be better if I put these in the article section? I treid that and I did not see it post, do these need approved before they are posted?
uochronos on 07/23/2004 01:47:54
i have never posted one but i believe admin has to actualy input it after its submited and he has alot one his plate right now so sometimes it takes awhile to get posted.... that would problay be the best place for stuff like this since it would give more people an oportunity to read it.
i just checked out www.mycarjams.com very interesting site and good prices.
mycarjams.com on 07/23/2004 01:50:54
Thanks, site is only 45 days old, I have a wholesaler close to me that is giving me great prices, only problem is they do not carry all the high end lines, as time goes on I would like to get more quality items up.
swez on 07/23/2004 20:06:49
I see you carry Kole Audio, Power Acoustik and SPL. How do these products compare to brands like Infinty, Alpine, JBL and other well known brands.
See a lot of Pyle, Legacy, Pioneer,Sony and a spate of other low cost amps. Any chance you'll be adding some of the top drawer brands and gear later?
See that the store offers Stiffening Caps. In your opinion, how effective are they and when is is appropriate to use a Power Cap?
Nice site you have started there MCJ. Welcome to CK and like to hear more from you as time permits.
Swez
Copyright ClubKnowledge 2009 * All Rights Reserved
